Safety device for forging machines



p 1964 A. R. KULL. 3,150,391

SAFETY DEVICE FOR FORGING MACHINES Filed June 22, 1961 3 Sheets-Sheet 1 FIG I IN V EN TOR.

ALBERT R. KULL BY ATTORNEYS P 1964 A. R. KULL 3,150,391

SAFETY DEVICE FOR FORGING MACHINES Filed June 22. 1961 3 Sheets-Sheet 2 INVENTOR.

ALBERT R. KULL ATTORNEYS Se t. 29, 1964 A. R. KULL SAFETY DEVICE FOR FORGING MACHINES 3 Sheets-Sheet 3 Filed June 22, 1961 INVENTOR.

ALBERT R. KULL Oberlin "Inks Domzfly ATTORNEYS FIG 5 United States Patent 3,156,391 SAFETY DEVliJE FOR FORGING MACHINES Albert R. Kull, Beachwood, Shin, assignor to The Ajax Manufacturing Company, Euclid, Ohio, a corporation of Ohio Filed dune 2, 1961, Ser. No. 118,8ll 5 Claims. (6!. 16-23) This invention relates generally, as indicated, to a safety device for forging machines and more particularly to a forging machine and safety throw-out mechanism therefor which will immediately stop operation of the machine should a workpiece be improperly positioned.

In forging machines of the type having a pair of grip ping dies and a reciprocable header die adapted to upset or shape the projecting ends of workpieces gripped by such gripping dies, the forgin operation may be such that the heading die or heading tool carried by the header may on occasion grip the workpiece and pull the same longitudinally out of the gripping dies. This may result from the workpiece being improperly gripped by the gripping dies and if such workpiece becomes wedged or jammed in the heading tool, it may be pulled from the gripping dies.

Since most such forging machines have a series of work operation stations located in a plane and a mechanism for transferring the workpieces progressively along such plane to the successive work stations, it can readily be seen that, if a workpiece is pulled from the gripping dies, continued automatic operation of the machine will be impossible. Once the workpiece is pulled from the gripping dies, the workpiece may be distorted or generally hairpinned and subsequent die damage may result.

It is accordingly a principal object of the present invention to provide a forging machine incorporating a mechanism which will automatically stop such machine if the eading tool pulls the workpiece from the gripping dies.

It is yet another main object to provide a forging machine having a workpiece position sensing mechanism which will automatically stop the machine if the workpiece is improperly located for the forging operation.

It is another main object to provide a safety device for a forging machine and the like wherein such workpiece position sensing mechanism may conveniently be operated by the reciprocation of the heading tool.

It is yet another object to provide a safety throw-out mechanism for forging machines which will automatically stop the operation of such maclnne should a workpiece be pulled longitudinally from the gripping dies by the shaping die.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drav ings setting forth in detail a certain illustrative embodiment of the invention, this being indicative, however, of but one of the various ways in which the principle of the invention may be employed.

In said annexed drawings FIG. 1 is a somewhat diagrammatic top plan view of a well-known forging machine incorporating the present invention;

FIG. 2 is a fragmentary enlarge top plan view of such machine showing the details of the present invention;

PEG. 3 is a fiagrnentary vertical section taken substantially on the line 3-3 of FIG. 2;

FIG. a rragrnentary side elevation of the mecha- 3 as seen from the right thereof;

3,15%,391 Patented Sept. 29, 1964 ice FIG. 5 is a view similar to FIG. 4 taken from the opposite side of FIG. 3; and

FIG. 6 is a fragmentary vertical section taken substantially on the line 6-6 of FIG. 2.

While the present invention will be seen to have many applications, it is illustrated as applied to a forging machine as the type shown in Leinweber Patent No. 2,796,- 616 which is a well-known forging machine manufactured by the Ajax Manufacturing Company, Cleveland, Ohio. Such machines are widely known and used.

Referring now more particularly to said annexed drawing and especially to FIG. 1 thereof, the embodiment of my invention illustrated herein is adapted to be installed on a horizontal forging machine of such well-known type which may comprise a main frame It carrying fixed gripping dies 2 and 3 held thereto by suitable clamps 4 and 5 and opposed cooperating movable gripping dies 6 and 7 mounted on a reciprocahle die slide 8 by clamps 9 and Hi. When dies 6 and 7 have been reciprocated toward stationary dies 2 and 3 to grip a blank B therebetween, a heading tool 11 carried by header slide 12 may be reciprocated axially of such blank to upset and shape the protruding ends thereof to form, for example, a hexagonal bolt head or other desired shape. Wh le such machines are commonly employed to form bolt heads, the illustrated machine and dies are especially adapted for the cold extrusion of starting motor shafts. A work transfer mechanism shown generally at 13 and described more in detail in my copending application, Serial No. 12,439, filed March 2, 1960, entitled Transfer Mechanism for Forging Machines, may be employed to shift the blanks B along a vertically extending plane from one set of vertically spaced opposed die cavities within the dies to another.

The reciprocation of the gripping die slide 8 and the header die slide 12 may be obtained from the main crankshaft of the machine which is powered by an electric motor 14 which is operative to drive a large flywheel 15 which is provided with an air operated clutch and brake 17. It will readily be understood that the heading tool ll which is clamped to the header slide 12 will be provided with a series of cavities or the like to shape progressively the protruding ends of the blanks B which are held in the various vertically spaced cavities or work stations of the machine. When cold extruding, for example, starter motor shafts, there is a tendency of the blanks to become wedged within the cavities of the forging tool 11 and if the gripping dies are not sufficiently gripping the workpiece, the blank 13 will be pulled longitudinally out of the gripping dies when the slide 12 and the tool 11 clamped therein are retracted from the gripping dies. It can readily be seen that should this occur, the next stroke of the heading tool may then bend the extended blank into hairpin shape and will probably considerably damage the dies of the machine. Moreover, such would preclude the high speed automatic operation of the maclune. In order to halt the operation of the machine to prevent such machine damage, there is provided a safety mechanism shown generally at 26 which is adapted to sense the position of the blank B to halt the operation of the machine should the blank be pulled longitudinally out of the gripping dies.

As seen perhaps more clearly in FIG. 6, the header slide 12 is mounted within a recess 21 in the frame between a stationary side liner 22 and an adjustable side liner 23, the adjustment of such liner being obtained through nuts 24 and 25. Lip liners 26 and 27 also provide support for the header slide 12. Such slide is pro vided with a cavity or recess 28 in which the heading tool 11 may be clamped by a clamping plate bolted in threaded apertures 29 shown more clearly in H6. 2. For clarity of illustration, the forging tool is shown removed in FIG. 6 and the forging tool clamp is omitted. Cover plates and 31 extend over the top of the header slide and such are bolted directly to the machine frame as shown at 33 and 34 respectively.

The header slide 12 is shown in its maximum extended position in FIG. 2 and it can be seen that a considerable recess shown at 36 is provided between the face of the header slide and the gripping dies 3 and 7. Also it is noted that the tool 11 extends beyond the face of the header die slide to engage and upset the ends of the blanks B held between the gripping dies. Since the tool stroke will, in the illustrated embodiment, be approximately 9 inches, it can be seen that when retracted, both the tool and header slide will clear safety contact flag 40 of the safety mechanism 20 which is mounted on shaft 41 for oscillation about an axis parallel to the axis of the blanks B. Such shaft 41 is mounted in bearings 42 and 43 which are in turn mounted on the slide cover plate 31 as shown at 44 and 45. An arm 46 is secured to the back end of such shaft and has a roller or cam follower 47 thereon adapted to engage the top or cam surface of linear cam 48. Such cam is secured directly to the top surface of the header slide for movement therewith as by the bolts 49. Such bolts are secured through elongated slots 50 in a bracket 51 so that the position of the linear cam can closely be adjusted to control the oscillatory movement of the shaft 41. The opposite end of the arm 46 is provided with a pivotal connection '53 connecting such arm to a push-rod 54 extending downwardly through openings 55 and 56 in horizontally extending portions 57 and 58 of the machine frame 1. A spring 59 surrounds such rod between the horizontally extending portion 58 of the frame and a collar 60 secured to such rod. It can now be seen that the pressure of the spring 59 will force the rod upwardly to-force the arm about the shaft axis to hold the roller 47 in engagement with'the linear cam 48. Accordingly, reciprocation of the header slide will impart a controlled oscillation to the shaft 41.

The flag lever or arm 40 is fastened to a lever bracket by means of cap screws 71 or the like and such lever bracket is provided with an aperture 72 for the reduced diameter end portion 73 of the shaft 41. A circular retainer 74 may be bolted directly to the end of such shaft as shown at 75. 'Keyed or otherwise secured to rotate with the reduced diameter end portion 73 of the shaft 41 is a hub member 76. A hub plate 77 is secured to the flat surface 78 thereof as by cap screws 79 or the like and such hub plate is connected to a lever bracket plate 80 by means of a spring 81 and a rod 82. Such rod is provided with a cap 83 on one end and a nut 84 threaded on the other end. The compression spring 81 acts to force the plates 77 and 80 apart Whereas the position of the nut 84on the rod 82 limits the extent to which they may be pushedapart. The plate 80 is secured to the flattened end 85 ofrthe lever bracket 70 by means of cap screws 86 or the like. Q

It can now be seen that oscillation of the shaft 41 will cause oscillation of the hub 76 keyed thereto which through the plate 77, the compression spring 81 and the plate 80 will cause oscillation'of the bracket 70 and the arm 40 secured thereto, the extent of such oscillation being shown by the full and phantomline positions of the lever in FIG. 3. Thus when the heading tool 11 is retracted'by the retraction of the slide 12, the linear cam 48 mounted thereon will cause the arm 46to pivot upwardly to cause the shaft41 to oscillate to move the flag from the phantom line position into the full line position. ,When in position, the flag willmove in frontof the heading tool 11 within the recess '36. Such flag is provided with a flat edge 87 whichis adapted to contact an elongated workpiece pulled from the'gripping dies by theheading tool 11 in any of the vertically spaced forging stations shown. 7 It is noted that the shape and positionof thearm is such that con- 7 tact with a blank 88 in the" lowermost cavity .orwork stad tion and contact with a blank 89 in the uppermost cavity or work station, or for that matter with any of the blanks in the vertically spaced work stations, will cause the same extent of relative movement of the arm 40 with respect to the hub 76. A microswitch 90 is mounted on the top thereof and should the flag contact a workpiece, the shaft 41 will continue to oscillate to the end of its stroke compressing spring 81 to cause an adjusting screw 91 to engage the button 92 of the microswitch 90. (See FIG. 2.) Actuation of such switch immediately operates a solenoid operated valve to disengage the clutch and apply the brake to halt the operation of the machine. Such oper-ation of the machine can be halted almost immediately to prevent the heading tool 11 from being reciprocated toward the gripping dies to smash the pulled out workpiece, the position of which has thus been detected by the arm 40.

Accordingly, there is a slight lost motion provided between the arm 40 and the shaft 41 when a workpiece is detected as accomplished by the spring and rod mechanism interconnecting the plates 77 and 80. This slight relative movement or lost motion is then effective to cause the switch 90 to stop the operation of the machine.

It can now be seen that there is provided a forging machine which will automatically stop its operation should the heading tool pull a workpiece longitudinally from the gripping dies thereby preventing possible extensive damage thereto.

Other modes of applying the principles of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed,

I, therefore, particularly point out and distinctly claim as my invention:

1. A safety device for forging machines of the type having a frame, a stationary gripping die, a horizontally reciprocable gripping die adapted to be reciprocated into and out of cooperative work-gripping relationship to said stationary die, and a third die horizontally reciprocable in a direction normal to such reciprocation of said reciprocable gripping die to engage and upset an end portion of an elongated cylindrical workpiece thus gripped by said gripping dies; said safety device comprising a shaft, means mounting said shaft on said frame for rotational movement, an arm mounted on said shaft, means responsive to movement of said third die to rotate said shaft and thus said arm into position between said third die and said gripping dies when said third die is retracted to engage such workpiece if pulled from said gripping dies by said third die, and means responsive to engage-' ment of said arm with such workpiece to halt operation of said machine.

2. The safety device of 'claim 1 wherein said means responsive to engagement of said arm with such workpiece to halt operation of said machine includes means operative to cause relative rotational movement between said arm and said shaft when said arm engages such workpiece, and switch means operative to halt operation of said machine in response to such relative rotational movement.v 60

mounting said shaft on said frame for rotational movement 3. The safety device of claim 2 wherein said means includes a linear cam mounted on said third die for movement therewith, a transverse member mounted on said shaft, and a roller mounted on said transverse member A for engagement with said cam during movement thereof.

4. The safety device of claim 2 wherein said means operative to cause relative rotational movement between said arm and said shaft includes a bracket means mounting said arm on said shaft for such relative rotational movement, a hub plate rigidly mounted on said shaft adjacent said bracket means, and spring means disposed between said'bracket means and said hub plate for yield-. I

inglymaintaining'the relative position of said armon said shaft. 7 r

5. In an upsetting forging machine of the type having a frame, a pair of gripping dies, a header die reciprocable in a direction to engage and upset an end portion of an elongated workpiece gripped by said gripping dies, and a plurality of vertically spaced Work stations in said gripping and header dies; workpiece position sensing means comprising a shaft, means mounting said shaft on said frame parallel to the direction of movement of said header die for oscillatory movement, an arm mounted for oscillation on said shaft, said arm including a linear workpiece engaging portion offset from the axis of said shaft, means operative in timed relation to the reciprocation of said header die to oscillate said shaft and thus said arm to move the work engaging portion thereof into position etween said header die and said gripping dies when said header die is retracted to engage a workpiece if pulled away from any of said vertically spaced work stations, means mounting said arm on said shaft for relative ro tational movement therebetween when the linear portion of said arrn engages such workpiece, and means responsive to such relative rotational movement to halt operation of said machine.

References (Jited in the file of this patent UNITED STATES PATENTS 451,534 Turner May 5, 1891 2,796,616 Leinweber June 25, 1957 2,890,778 Braun et al. June 16, 1959 

1. A SAFETY DEVICE FOR FORGING MACHINES FOR THE TYPE HAVING A FRAME, A STATIONARY GRIPPING DIE, A HORIZONTALLY RECIPROCABLE GRIPPING DIE ADAPTED TO BE RECIPROCATED INTO AND OUT OF COOPERATIVE WORK-GRIPPING RELATIONSHIP TO SAID STATIONARY DIE, AND A THIRD DIE HORIZONTALLY RECIPROCABLE IN A DIRECTION NORMAL TO SUCH RECIPROCATION OF SAID RECIPROCABLE GRIPPING DIE TO ENGAGE AND UPSET AN END PORTION OF AN ELONGATED CYLINDRICAL WORKPIECE THUS GRIPPED BY SAID GRIPPING DIES; SAID SAFETY DEVICE COMPRISING A SHAFT, MEANS MOUNTING SAID SHAFT ON SAID FRAME FOR ROTATIONAL MOVEMENT, AN ARM MOUNTED ON SAID SHAFT, MEANS RESPONSIVE TO MOVEMENT OF SAID THIRD DIE TO ROTATE SAID SHAFT AND THUS SAID ARM INTO POSITION BETWEEN SAID THIRD DIE AND SAID GRIPPING DIES WHEN SAID THIRD DIE IS RETRACTED TO ENGAGE SUCH WORKPIECE IF PULLED FROM SAID GRIPPING DIES BY SAID THIRD DIE, AND MEANS RESPONSIVE TO ENGAGEMENT OF SAID ARM WITH SUCH WORKPIECE TO HALT OPERATION OF SAID MACHINE. 